nUcLeArEnVoY |
11-03-2023 05:21 PM |
I replaced the heater core recently in my '79 Trans Am. They do reproduce copper/brass units for my car, thankfully, so I splurged and got that off of Ames. They're made by TSM and it fit perfectly. I vacuum-tested mine prior to install, and so far, no leaks and blows as hot as my 160-degree stat and upgraded cooling system will allow.
A lot of the time, installer error is a reason these new heater cores fail, and by installer error, I mean forgetting to restrict flow to it. During sudden high throttle situations, the hammer of water that rushes to the heater core could end up leading to early failure in an unrestricted inlet line to the core. That's why a lot of early Pontiac motors where the heater inlet came off the intake had an issue with failed heater cores. They eventually started implementing a bi-metallic coil into the heater hose nipple fitting at the rear passenger cylinder head, though the jury is out on the exact purpose of this coil - some say it is to restrict flow until the coolant temp reaches a certain point, others say it was to help with engine warm-up. In later Pontiac motors, the nipple instead just had a rubber restrictor inside them, restricting flow to 0.250. This restriction effectively dampens the slug of water to the heater core in high throttle situations, lengthening the service life of the unit. Police service units from the factory had the extra restriction in place since they're often operated with sudden high throttle.
When I replaced my heater core, I also replaced the rear passenger head nipple, since my engine still had the original nipple on it, and the rubber restrictor was missing. Probably dissolved after someone did a cooling system flush with strong chemicals in the past, and so my heater core was getting unrestricted flow which is what probably contributed to its failure. It was still the original Harrison heater core. To be extra safe, I also got a 1" aluminum spacer from McMaster Carr with a 0.250 hole and stuck it in-line in the inlet heater hose to act as an extra restriction like how the police units came.
The main issue I hear about with the aluminum cores is fitment inside the heater box and trying to slip the tubes through the firewall. All heater cores are rigorously tested for leaks before being sent out, so if you follow your due diligence and also make sure that you have restrictions to the heater core in place as from the factory, I'm sure it will last you many years of service.
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